Does anyone know to unlock a Power On Password off a Thinkpad A20m (2628-41U)? I have bought the laptop off eBay and the seller didn't know the Power On Password. Not sure if there are other means to remove the password besides removing the CMOS battery, which didn't work.

 

these are IBM's official instructions.... sounds like you already did this? If this is not working, the same document says the systemboard must be replaced.

full PDF:
http://www.mbhs.edu/~jaosborn/23p0896.pdf

How to remove the power-on password

To remove a POP that you have forgotten, do the
following:

(A) If no SVP (Supervisor Password) has been set:

1. Turn off the computer.

2. Remove the battery pack.

Related service information
28 ThinkPad A20m/p, A21m/p, A22m/p
For how to remove the battery pack, see “1010 Battery
pack” on page 60.

3. Remove the backup battery.

For how to remove the backup battery, see “1040
Backup battery” on page 66.

4. Turn on the computer and wait until the POST ends.
After the POST ends, the password prompt does not
appear. The POP has been removed.

5. Reinstall the backup battery and the battery pack.

(B) If an SVP has been set and is known by the servicer:
1. Turn on the computer by pressing and holding F1.
2. Enter the SVP. The IBM BIOS Setup Utility menu
appears.
3. Select Password, using the cursor keys to move down
the menu.
4. Select Power-On Password.
5. At the Enter Current Password field, enter the SVP.
6. When the Enter New Password field opens, leave it
blank and press Enter twice.
7. In the Changes have been saved window, press Enter.
8. Press F10; then, in the Setup confirmation window,
select Yes .